1. Field of the Invention
The invention relates to a process for electroplating certain metals including gold, gold alloys, nickel and tin-lead.
2. Description of the Prior Art
Gold electroplating processes have many important industrial applications. Particularly important, especially in recent years, is the application of gold plating processes to the manufacture of electronic circuits. Because of its electrical conductivity properties and the fact that it does not form a surface insulating layer, gold is especially useful as a conductor in electrical circuits as well as a surface metal in electrical contacting areas. Because of the extensive use of gold in electrical circuits as well as its high cost, it is advantageous to conserve as much as possible the amount of gold used in a particular application without sacrificing in the quality of the electronic circuits.
In present practice contact fingers in electronic circuits are electrically connected together by a bus wire and gold electroplated as one plating surface. The variation in the uniformity and thickness of such gold platings is quite large which requires thicker plating to insure minimum coverage on all fingers. Further, contact fingers which are not going to be used in a particular application as well as the bus wire which is subsequently removed from the board and discarded receive the same or greater thickness of gold as the contacts which are to be used. This is again wasteful of gold. Considering the increasing use and cost of gold, it is highly desirable to reduce the amount of gold used without sacrifice in the quality of device produced.